The invention relates to improvements in an automatic machine for uprightly positioning and continuously feeding containers, of any shape and size, in particular lightweight articles, such as empty plastic bottles. This machine is designed for continuous feeding of other machines such as high production filling machines or similar equipment.
Known machines of the type to which the present invention relates may include in general:
a) a hopper of any shape or dimension to receive in bulk containers that fall onto a bottom plane whose edges are at a distance from the side wall of the hopper providing a space allowing the passage of the containers;
b) a structure, provided with displacement means in an enclosed circuit, located below the bottom plane, including, fully or in part:
a plurality of pockets at the periphery of the structure, adapted to receive containers in a lying position and provided with retaining means for one part of the containers, namely their neck, in such a way as to release them in a predetermined position, usually with the neck upward; PA1 a plurality of discharge chutes provided under the pockets for receiving and transferring the containers, correctly oriented, towards an exit conveyor that feeds, for example, a bottling line; PA1 an endless belt provided having holes connected to a pneumatic suction chamber which function to retain the containers steady on the belt, supported by their bottom; this does not cause the containers to approach each other, but holds them at a distance approximately equivalent to their spacing in the discharge chutes, so that the above-mentioned forces tending to tip the bottles during their motion create frequent disruptions; PA1 a rotating star-shaped element that functions to take each container removed from the discharge chute of the machine to transfer it onto the moving conveyor belt; this requires a perfect synchronization between the displacing speed of the chutes and the star-shaped element displacement speed, so that in case of an incorrect synchronization or positioning of the containers, they are crushed. PA1 at least one first means for braking and dragging containers, having a translation movement located on the run of the containers, along a first portion of the moving conveyor belt immediate to the container exit of the positioning machine, which action decreases the output and forward speed on the moving belt of said containers to effect a relative movement of the containers toward each other, the first means cooperating in addition to maintain the containers in an upright position and ejecting out of the conveyor any containers that are accidentally turned down or tipped over; PA1 a second means for braking containers that operates transversely and laterally on the run of the containers on the moving conveyor belt, located downstream of the first means, thereby restraining the containers to effect further relative movement of the containers until they are closely adjacent side by side, and to allow their passage in this condition by a permanent interaction with the second braking means.
c) a plane or shelf, located below the pockets and over the chutes, designed to support the containers when they are conveyed by the pockets, the plane or shelf being provided with an opening in an unloading area through which the containers drop when moved into position thereover by the container holding elements;
d) a linear moving conveyor, provided with lateral supporting bars, which moves underneath the chute section along a path generally tangent to the path of movement of the chutes an the containers therein, to receive the containers from the chutes and transport them in alignment away from the machine; and
e) means to assist in gently transferring the containers from the lower section of the chutes onto the linear moving conveyor;
There are many forces tending to unbalance the bottle during the bottle's transfer from the displaceable chutes to the belt of the moving conveyor. The plastic bottles leave the circular or enclosed circuit motion thereof with the drum of chutes and their motion is changed to a generally linear motion with the moving conveyor. The inertia force due to movement with the chute in an enclosed circuit tends to tip the bottle over outwardly from the drum. There is also an inertia force tending to tip the bottle forward. All these forces are of particular importance mainly because of the distance between the bottles imposed by the separation of the discharge chutes. In addition, in bottle of petiolate type (PET bottles) with a small supporting bottom the conditions of transport are still more difficult.
Machines known to the applicant of the type referred are described in the following U.S. Pat. Nos. 3,295,659; 3,650,368; 4,130,194; 4,865,181; 4,681,209 and 4,928,808.
Among the known means to convey containers when they exit the positioning machine, there exist: